manual broaching

[sorrelcreek]

I had to broach a metric key way today so instead of buying a broach and machining the broach guide I made this tool a long time ago and just grind high speed steel to the size I need and manual broach with the milling machine.

 

[EricB]

Cool. Do you have a slotting-head for the mill, or what drives the broach? Just lock the spindle and use the quill feed?

 

[sorrelcreek]

Nope good old fashion manual elbow grease. Just use the quill handle and only feed in a few thousands of an inch at a time and work your way to your deapth.

 

[Alexander]

Yeah that works great. I did that on my lathe one time and it worked brilliant. Precision wasn't too important in my case I simply used a little hss blank to cut the internal key.

 

[sorrelcreek]

Yes absolutely it works great that way on the lathe also just as long as it's in your lowest gear so the chuck doesn't move on you. Before I got my mill I've had to get quite creative with my lathe sometimes it's interesting trying to figure out how to do a job when you don't have all the easy tools in front of you. That's what I like the most about machining is figuring out how to set up the part using some sort of jig or the machine to get the job done.

 

[Janger]

How is the hss cutter held in place in the hole? Is it triangular and just wedged in? Does the other side look different? Screws? Is that a screw in the bottom ?

 

[sorrelcreek]

It's just held in with a set screw made the hole so a 1/4 hss will be a nice fit inside. I've got a couple of these bars with different size holes for different hss. The bar is only 4 inches long and the part is only about 2 inches long. It's also just held in my nmtb 40 holder with a collet. You could use a hss boring bar that you can buy for the lathe with a square hoke but as long as your not taken big cuts I've never had a problem with this setup, it's only took me a half hour to machine the bar and grind the hss to size and very little money for a one off part, wasn't worth the money or waiting time for a broach. Hope this answers your questions